1. Field of the Invention
This invention relates to rolling mills for edging metal sections, and more particularly to rolling mills for edging H- and other similar sections having gap-variable rolls of the eccentric ring type and having shiftable rolls in the roll axial direction. An edge rolling mill according to this invention permits rolling, for example, H-sections with different web heights and flange widths by simply adjusting the gap between drive side and work side rolls off the mill line, without changing the rolls themselves.
2. Description of the Prior Art
The conventional edge rolling mill that applies rolling to the flanges of an H- or other similar section is provided downstream of a universal mill that rolls the section in several passes.
When multi-pass rolling is performed on the conventional one-piece edge rolling mill, however, a gap S forms between a web 4 of an H-section 1 and a horizontal roll 8 as shown in FIG. 1 (a). As a consequence, a flange 2 of the H-section 1 causes buckling 6 as shown at FIG. 1 (b) or the web 4 becomes off-centered with respect to the flanges 2 as shown in FIG. 1 (c).
To solve this problem, Japanese Provisional Patent Publication No. 77107 of 1987 proposed an eccentric-ring edge rolling mill which comprises separate pairs of horizontal rolls to work on the flange edges of the section being rolled and ring rolls to hold its web. The web-restraining ring rolls are eccentric with respect to the horizontal rolls and always in contact with the web of the section. This eccentric-ring edge rolling mill 11 is made up of a pair of horizontal rolls 13, with a rotatable eccentric ring 15 fitted over each horizontal roll 13 through a bearing 14, as shown in FIGS. 2 and 3. Then, a rotatable web-restraining ring roll 17 is fitted over the eccentric ring 15 through a bearing 16. A worm wheel 18 provided on the eccentric ring 15 and a worm 19, in combination, rotate the eccentric ring 15, thereby positioning the web-restraining ring roll 17 eccentric to the horizontal roll 13.
This edge-rolling mill 11 has several shortcomings. The need to leave a large enough space for a device to apply a driving force to the inner side of the eccentric ring 15 makes it difficult to bring the two eccentric rings 15 closer. This, in turn, does not permit reducing the gap between the two web-restraining ring rolls 17 adequately and, therefore, securing a large enough variable range of web height. As mentioned before, this mill 11 is made up of a pair of horizontal rolls 13 each of which is fitted over a horizontal roll shaft 12 and carries therearound a rotatable web-restraining ring roll 17 having an eccentric ring 15. Because of this construction, the web-restraining ring rolls 17 are not firmly supported. The lack of their stability and rigidity does not permit rolling with heavy reduction. Besides, the large diameter difference between the horizontal rolls 13 and web-restraining ring rolls 17 does not permit the rolling of a section 1 with small flange thickness on the same mill.